At first glance, it looks like 13 girls (yes, we counted). However, if you take a closer look, you’ll notice that the girls are positioned a little too perfectly and the shadows are going in opposite directions.

Want the real answer? It’s two, so says the photographer who uploaded the picture to Instagram.

Here’s how it works: The first two girls you see are actually sitting in between two mirrors–thus creating this never-ending optical solution. How cool is that?